This disclosure relates generally to polymeric foams with nanocellular morphology and methods of making the polymeric foams.
Polymer foams have been prepared by diffusing a polymer blowing agent and/or foaming agent into the desired polymer. Solubility of the polymer-blowing agent in the host polymer is a factor that can determine the cell size. Solubility is generally limited such that microcellular morphology is the smallest cell size attainable with various blowing agents and polymer systems. In the past, solubility was increased by use of a high-pressure gas injection system, which is relatively expensive due to the high-pressure requirements. A disadvantage of this process is that, when the polymer is made into pellets and shipped to customers, the gas diffuses out of the pellets, and further foaming using a conventional extruder without adding blowing agent is difficult.
Therefore, remains a need in the art for foamable polymer materials that can be pelletized and transported while retaining the ability to produce a nanocellular morphology.